Calcium citrate vs Calcium carbonate

[Kathrynne Holden, MS, RD]

Colleagues,
Occasionally the topic of calcium comes up, especially with regard to
different types of calcium. I just received this information and pass it
on, FWIW.
Best,
Kathrynne
******************
CALCIUM CITRATE TRUMPS CALCIUM CARBONATE IN
OSTEOPOROSIS STUDIES

DALLAS - November 23, 1999  - Three studies from UT Southwestern Medical

Center at Dallas researchers show that calcium citrate is better
absorbed than
calcium carbonate and is effective at preventing osteoporosis in early
post-menopausal women.
     Osteoporosis - or brittle-bone disease - is a major health threat
to 28 million
Americans. About 10 million have the disease, and 18 million more are at
increased
risk due to declining bone density caused by loss of calcium within the
bones. Forty
percent of women and 13 percent of men will suffer a bone fracture due
to
osteoporosis in their lifetime.
     "It is well-recognized that calcium supplements taken at the proper
time can help
prevent bone loss in elderly patients," said Dr. Khashayar Sakhaee,
chief of mineral
metabolism. "We are interested in seeing which formulation is most
beneficial in
preventing osteoporosis and in maintaining bone density in early
post-menopausal
women."
     Two of the studies compared calcium citrate with calcium carbonate
to see
which was better absorbed. Sakhaee and colleagues published their
analysis of data
from 15 previously published randomized trials evaluating
bioavailability (the amount
of calcium absorbed from a supplement, rather than the amount of calcium
a
supplement contains) in the November-December issue of the American
Journal of
Therapeutics. The second study, published by Dr. Howard Heller,
assistant
professor of internal medicine, and collaborators, in the November issue
of the
Journal of Clinical Pharmacology compared the absorption of two
over-the-counter
calcium supplements - Citracal (calcium citrate) with Os-Cal (calcium
carbonate).
The researchers used classic pharmacokinetic techniques of measuring
peak and
cumulative increase in blood calcium concentration over six hours
following a single
oral dose instead of the indirect method of measuring change in urine
calcium
excretion.
     A third study, published by Sakhaee, former UT Southwestern faculty
member
Dr. Lisa Ruml and co-workers, also reported in the November-December
issue of
the American Journal of Therapeutics, compared the effect of calcium
citrate vs. a
placebo in preventing bone loss in early post-menopausal women.
     All three studies confirmed the benefits of calcium citrate. The
conclusion from
the 15-trial analysis was that calcium citrate was absorbed 22 percent
to 27 percent
better than calcium carbonate when taken either on an empty stomach or
with
meals. Heller's study of commercial calcium preparations concluded that
Citracal
was more "bioavailable" than Os-Cal; it was absorbed faster and to a
greater
extent.
     "Our results show that even under the most favorable conditions,
calcium
carbonate is not nearly as well-absorbed as calcium citrate," Heller
said. "We were
surprised at the magnitude of the difference in absorption rates - with
calcium citrate
being absorbed two and a half times better than calcium carbonate."
      The third study - the first of its kind - showed the benefits of
calcium citrate in
early post-menopausal women. During the two-year study, 57 women in
early
menopause (five years into menopause) and six mid-menopausal women (five
to10
years into menopause) took either 800 milligrams of calcium citrate or a
placebo
daily. Those taking calcium citrate averted bone loss by stabilizing the
bone density
in their spine, in the top part of the thigh bone (a common site of hip
fractures) and
in the small bone of the forearm. Women taking the placebo had a
significant
decrease over the two-year period in the densities of the spine and
forearm, but
showed no change in thigh-bone density.
     "This study shows that calcium-citrate treatment may be used alone
in the
prevention of skeletal bone loss in early post-menopausal women," said
Sakhaee.
"The long-term effectiveness of calcium citrate is a particularly
exciting therapeutic
finding."
     UT Southwestern mineral metabolism researchers developed Citracal
in
conjunction with Mission Pharmacal of San Antonio.
###
--
Kathrynne Holden, MS, RD
Medical nutrition therapy for Parkinson's disease
Author: "Eat well, stay well with Parkinson's disease"
"Parkinson's disease: assessing and managing unique nutrition needs;"
"Risk for malnutrition and bone fracture in Parkinson'sdisease,"
J Nutr Elderly. V18:3;1999.
http://www.nutritionucanlivewith.com/